Flint learned that cheaper water came at quite a price. Shutterstock

The lead crisis in Flint has been public since October and suspected long before that. But things were bad in the Michigan city long before its tap water turned out to be unsafe.

Lead poisoning affects brain development so much that the gradual reduction of lead poisoning in American society has worked something of a miracle. Exposure to lead — and no amount of exposure is now considered safe — can lead to learning disabilities, lower IQs, and impulsivity. Those effects, multiplied over a city or state or country, are costly.